Organoiridium catalyzed hydrogen isotope exchange: ligand effects on catalyst activity and regioselectivity

Shu, Arthur Y. L.; Chen, W.; Heys, J. Richard

doi:10.1016/s0022-328x(96)06413-3

Cited by 78 publications

(53 citation statements)

References 9 publications

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“…It had been assumed by ourselves and by previous workers, 5 that the kinetics of exchange with complexes 1 would be comparable to those of complexes such as 2 and 4, where exchange is largely complete within 24 h. 2,4 However, this assumption proves to have been incorrect. Not only is exchange using 1a comparatively slow (Figure 1), but exchange into phenylacetone is very much slower than into acetophenone.…”

Section: Resultsmentioning

confidence: 92%

An improved bidentate complex of iridium as a catalyst for hydrogen isotope exchange

Herbert

Kohler

McNeill

2005

J Label Compd Radiopharm

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SummaryIridium(I) complexes 1, containing bidentate phosphines, and 3, with arsine ligands, are generated in situ. These species mediate hydrogen isotope exchange in a variety of aromatic substrates including benzyl ketones. Although the catalytic activities of complexes 1 and 3 are generally unexceptional, a logical step leads to the use of [ethylene-1,2-bis(diphenylarsine)](cyclooctadiene)iridium(I) tetrafluoroborate (5), which is an efficient catalyst for both aryl and benzyl ketones, and mediates exchange to a substantial extent in other substrates also.

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Section: Resultsmentioning

confidence: 92%

An improved bidentate complex of iridium as a catalyst for hydrogen isotope exchange

Herbert

Kohler

McNeill

2005

J Label Compd Radiopharm

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“…Despite the growing list of compatible directing groups, we [23] and others [24][25][26][27] have found these developed C-H activation methods less applicable in the labelling of aromatic esters under ambient conditions. Herein, we report the extension of our methodology to encompass the labelling of weakly coordinating benzoate ester derivatives under mild conditions.…”

Section: Introductionmentioning

confidence: 97%

Iridium-Catalysed ortho-Directed Deuterium Labelling of Aromatic Esters—An Experimental and Theoretical Study on Directing Group Chemoselectivity

et al. 2015

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Herein we report a combined experimental and theoretical study on the deuterium labelling of benzoate ester derivatives, utilizing our developed iridium N-heterocyclic carbene/phosphine catalysts. A range of benzoate esters were screened, including derivatives with electron-donating and -withdrawing groups in the para-position. The substrate scope, in terms of the alkoxy group, was studied and the nature of the catalyst counter-ion was shown to have a profound effect on the efficiency of isotope exchange. Finally, the observed chemoselectivity was rationalized by rate studies and theoretical calculations, and this insight was applied to the selective labelling of benzoate esters bearing a second directing group.

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“…1 The technique could also be used in the preparation of deuterium-labeled molecules if its efficiency and reproducibility could be improved. Recent work from these laboratories includes some examples where better than 95% ortho-hydrogen exchange was observed, [2][3][4][5] raising the possibility that the technique might be applicable to the preparation of deuterated drug candidates for use as mass spectrometric standards.…”

Section: Introductionmentioning

confidence: 99%

Ligand effects upon deuterium exchange in arenes mediated by [Ir(PR₃)₂(cod)]⁺.BF₄⁻

Ellames

Gibson

Herbert

et al. 2003

Labelled Comp Radiopharmac

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SummaryA series of complexes of general form [Ir(PR 3 ) 2 (cod)] + has been prepared and used, without isolation, to mediate deuteration of a range of model substrates. The data suggest that, with many substrates, basicity of the phosphine ligands bound to iridium is an important factor influencing substrate selectivity and the efficiency of deuteration. In addition, the spectrum of activity of iridium complexes bearing pure donor ligands is different in many cases to that of complexes where the ligands are known to be p-acids.

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Organoiridium catalyzed hydrogen isotope exchange: ligand effects on catalyst activity and regioselectivity

Cited by 78 publications

References 9 publications

An improved bidentate complex of iridium as a catalyst for hydrogen isotope exchange

An improved bidentate complex of iridium as a catalyst for hydrogen isotope exchange

Iridium-Catalysed ortho-Directed Deuterium Labelling of Aromatic Esters—An Experimental and Theoretical Study on Directing Group Chemoselectivity

Ligand effects upon deuterium exchange in arenes mediated by [Ir(PR₃)₂(cod)]⁺.BF₄⁻

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Organoiridium catalyzed hydrogen isotope exchange: ligand effects on catalyst activity and regioselectivity

Cited by 78 publications

References 9 publications

An improved bidentate complex of iridium as a catalyst for hydrogen isotope exchange

An improved bidentate complex of iridium as a catalyst for hydrogen isotope exchange

Iridium-Catalysed ortho-Directed Deuterium Labelling of Aromatic Esters—An Experimental and Theoretical Study on Directing Group Chemoselectivity

Ligand effects upon deuterium exchange in arenes mediated by [Ir(PR3)2(cod)]+.BF4−

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Ligand effects upon deuterium exchange in arenes mediated by [Ir(PR₃)₂(cod)]⁺.BF₄⁻